<!DOCTYPE html>
<html>
<head>
    <title>Logical Not Example 2</title>
    <script type="text/javascript">
    
        alert(!!"blue");     //true
        alert(!!0);          //false
        alert(!!NaN);        //false
        alert(!!"");         //false
        alert(!!12345);      //true


    </script>

</head>
<body>
  
</body>
</html>